1. Field of the Invention
The present invention relates to an optical branching device available for use in the field of optical communication, processing of optical signals and the like, and particularly to a waveguide type optical branching device. The optical branching device includes the optical directional coupler and branching waveguide.
2. Related Background Art
There have been known optical branching devices which branch light having been transmitted along one path into eight paths. Waveguide type optical branching devices with this 1.times.8 structure are often used in the field of optical communication, processing of optical signals and the like; an example thereof is described in Japanese Patent Application Laid-open No. 5-11130 (11130/1993).